Control device for hydraulic lines



Filed Feb. 2s, 1946 lNVENT-OR BY affon fl. /f/wg ATTORNEY Patented Apr.14, 1942 CONTROL DEVICE FOR HYDRAULIC LINES Garold A. Kane, Minneapolis,Minn., assigner to` Northern Pump Company, Minneapolis, Minn., acorporation of Minnesota Application February 23, 1940, serial No.320,392

14 Claims.

This invention relates to a device for controlling the ow of liquidbetween two lines or conduits containing liquid under pressure. Liquidis often supplied by one line under pressure to some form of apparatusactuated by said liquid or the liquid is placed under pressure in a lineby some form of apparatus such as a pump. In all of such cases there is,of course, a line having a liquid therein at lower pressure to which theliquid is supplied or into which it is exhausted or discharged. It isfrequently desirable to limit the pressure at which the liquid issupplied and to open means leading to the exhaust or dis- 1.

charge line when the pressure reaches a certain Point.

-It is an object of this invention to provide a simple and efficientdevice for controlling the flow of liquid between two lines inaccordance with the pressure developed.

It is a further object of the invention to provide a simple andefficientdevice for controlling the ow of liquid from one line or conduitcontaining liquidunder pressure to aline or conduit containing liquidunder lesser pressure, which device is operated by the liquid inaccordance .with the pressure developed and one in which there is anegligible leakage before the main operation thereof.

It is another object of the invention to provid a device such as setforth in the preceding paragraph including a control passage havingports -l of considerable size opening thereinto, which ports arecontrolled by a control valve or pilot valve to cause operation of thedevice, said ports of considerable size insuring that there will be noclogging of the device by dirt or otherl foreign material.

It i's also an object of the invention to provide such a device as aboveset forth having means for varying the pressure at which it willoperate.

It is still another object of the invention to provide a device `forcontrolling the flow of liquid from one line containing liquid underpressure to another line containing liquid under p ressure comprising aduplex device including a member having a relief passage with valves ateither end thereof similarly related to the lines of high and lowpressure respectively with a' control valve and passages disposedsymmetrically vto said valves with adjustable means for determining thepressure at which the device will operate so t that it can be usedforlimiting the pressure on either line, said means being differentiallyset for the desired operating pressures.

It is further an object-of the invention to provide a device controllingthe flow of liquid from one line containing liquid under `pressure toanother -line containing liquid under lesser pressure comprising amember having a relief passage, a valve normally closing said passageadapted to be operated by 'the pressure of the liquid and a controlvalve'to which is applied the full pressure of said first mentionedline, said control valve being operated upon a predetermined pres-y sureto cause opening Aof said first mentioned valve. l

These and other objects and advantages of the invention will be fullyset forth in the following description made in connection with theaccompanying drawing in which like reference characters refer to similarparts throughout the several views and in which:

Fig. 1 is a vertical longitudinal section through the device taken ondifferent planes.

vReferring to the drawing, a member'designated generally as I0 is shown,thesame having therein a passage IIla which will be referred'to as arelief passage. Said passage Ilia has valve seats Ib and Illc formed atthe ends thereof and valve seat VIlibis arranged to be engaged by avalve II having a portion formed on its vend of frustoconical formadapted to closely engage seat I lib.l

SeatIIlc is engaged by a similar valve I2. Valve II has associatedtherewith a plunger I Ia. While plunger IIa could be connectedi'withvalve II in various ways, in the embodiment of the invention illustratedit is shown as an integral part of said valve. Plunger IIa ts in andmoves in a cylindrical bore or chamber Ilid formed in member I0. ValveI2 has a similar plunger I2ty associated therewith which fits in andslides in a cylindrical bore or chamber Ille. Plunger I Ia hasacylindrical projection IIb at the side opposite valve II,

which projection is surrounded by one end of a compression coiled springI3, the other end of which surrounds a projection Ilia on the end of a'closing member or gland I4 having cylindrical portions seated' incounterbores in the end of member I 0. Member I4 will preferably be heldin place by a plurality of circumferentially spaced bolts I5 extendingthrough the same adjacent.

. projection I8aA on a closing member or gland I8 having cylindricalportions seated in counterbores inone end ofA member I0, which member tohold said valves to their seats. A control passage IIIf is formed inmember I0 preferably above passages Ind and Ille and while this pas-4sage might be of various forms, in the embodiment of the inventionillustrated it is shown as cylindrical. Passage If communicates at itsends with other bores or passages Illy and IIlh shown as of slightlylarger diameter than passage IUf, thus forming shoulders and plungerdisks 20 and 2| are disposed and fit respectively in passages Ig and |0hand normally engage the shoulders at the ends thereof adjacent passage I0f. Plunge disks 20 and 2| are engaged respectively by compressioncoiled springs 22 and 23, the other ends of which respectively engageplunger disks 24 and 25 also fitting in and slidable in passages Ig andIh respectively. Passages IIIg and I 8h are threaded at their outer endsand have screwed or threaded thereinto the ends of closing members orglands 26 and 21 respectively. Members 26 and 21 have shoulderedportions of different diameters thereon, the ones of smallest diametersbeing disposed in counterbores in member Il) and having their endsengaging gaskets 28 at the bottoms of said counterbores. 'I'heshouldered portions of largest diameter engage gaskets 29 contacting theouter ends of member I0 and having portions extending at right anglesthereto, one of which overlies the upper portions of members 26 and 21respectively and the lower portions of which are seated in smallrecesses formed in the ends of member I0. Members 26 and 21 have reducedand exteriorly threaded outer portions on which are threaded closedcylindrical caps 30, the ends oi which engage gaskets 3| disposedbetween the pressure.

.the ports of passages I072, IIlk:1 and Illm to equalige the pressure onvalve portions 34e, 34h and 34a. Conduit 35 will connect with the lineor conduit 36 carrying the liquid with the higher Another conduit 31 isconnected to member I0 and communicates with chamber Ille at the sideoffplunger I2a on which valve I2 is same and members 26 and 21respectively. Members 30 preferably will have part of their periphery ofangular formation so as to conveniently receive a wrench. Members 26 and21 are centrally bored and threaded to receive threaded and headedscrews 32 having reduced and pointed inner ends seated in small conicalrecesses in the plunger disks 24 and 25 respectively. JambA i nuts 33are disposed on screws 32 and engage the Outer ends respectively ofmembers 26 and 21. It will be noted as shown on the drawing that theends of screws 32 are disposed within caps 30. A valve member designatedgenerally as 34 i is disposed in control passage |0f, which valve may becalled a pilot valve or control valve. Valve 34 comprises a Vcentralreduced rodlike portion having ends which normally as illustrated engagedisks 28 and 2|. Said valve also has spaced portions or lands 34a, 34hand 34e. Land 34a controls, a port formed by a passage .lui extendingfrom passage |0f to relief passage Illa. Another passage Illi extendsfrom chamber Illd toward passage I 0f and has spaced passages I0y`1 andI 09'2 forming ports opening into control passage I0f. Another passageI0k extends from chamber Ille toward passage I0f and has spaced passages|I|lc1 and IIJIcl forming ports opening into control passage IIlf.Another passage IIIm has a port opening into passage I0f and extendstherefrom through member III to chamber |0d at one side of plunger IIawhich is the side opposite valve II. A similar passage IIin has'a portopening into .passage I0f and extends through disposed. Conduit 31connects with another conduit or line 38 which will contain the liquidunder the lesser pressure which is usually the exhaust or dischargeconduit. For more convenient reference the chamber in bore Illd at theside of plunger IIa on which valve II is disposed will be referred to aschamber IIJcl1 while the chamber at the opposite side o f said plungerwill be referred to as chamber |0122. The chamber at one side of plungerI2a will be referred to as IIIe1 while the chamber at the opposite sidewhich contains spring I1 will be referred to as chamber I Dez.

The operation of the device is as follows:

Let it be assumed that liquid is supplied for any purpose in conduit 36at considerable pressure. This liquid after passing through someapparatus or being used for some purpose is discharged into conduit 38at a lower pressure. It is desired to limit the pressure in conduit 36or to provide a certain differential between the two lines 36 and 38.The spring 23 will be set so that it will yield and plunger 2| will bemoved upon the attainment of a predetermined pressure. This pressure, ofcourse, can be'varied as desired by operation of the screw 32 which willcompress spring 22 to give the desired pressure. With the parts in thenormal position shown the high pressure from line 36 will be transmittedthrough pipe 35 to chamber |0111. This pressure will be transmitted fromchamber IIldl to passage Illi and passages |07'1 and |07'2 to controlchamber If at both sides of valve portion 34o.

The pressure will thus be transmitted through passage |0m from thechamber at the right of portion 34e to chamber |0d2. This high pressuretherefore acts upon the large area at the outer side of plunger IIa andsaid plungerl is held in position to keep valve II closed with its endagainst seat IIJb. It will likewise be seen that the lower pressure fromline 38 will be transmitted through conduit 31 to chamber Illel. rIfhispressure will be transmitted through passage lk, its branches I Ille1and 'Illlc2 and their prts to control passage `I0f at both sides ofvalve portion 34h. This pressure will also be transmitted from the lefthand side of portion 34h through passage IIJn to chamber Ille. There isthus the same pressure at .both sides of plunger I 2a and this pressureacting against the, large outer side of said plunger will hold valve I2in closed position with its end against seat |0c. Valve I2' is also heldclosed by spring I3. Springs I3 and I1 are of fairly light construction.When the predetermined pressure is reached at which it is desired tohave the device operate, the pressure upon the left hand ends of portion34e of valve 34 will cause said valve to move to the right and compressspring 23.by movement of plunger disk 2|. This causes valve portion 34eto move so that it will close the port of passage IM. When this port isclosed the high pressure supplied between Avalve portions 34o and 34a iscut oil. As valve Ila to the left, thus opening valve Ii. This willpermit the liquid from chamber AIlld1 to ow into relief passage a andthis'liquid being at much higher pressure than the liquid in chamberMiel, valve I2 will be opened against the pressureof light spring I1 andthe liquid can flow directly to the low pressure line 38. The device isused with pressures which are quite high and is often i used where the'liquid pumped is oil. It has been a problem of prior devices to preventleakage when the pressure became high and approached the relief point.With the present construction the valve portions 34e and 34a are soarranged with ports from passages I 07'2 and Illi that the portion 36ais just opening passage |02' as passage |07? is closed by portion 36e.No leakage can thus occur until just at the point when the deviceoperates. might possibly occur is so. small as to be negligible. Inpractice it has been found that valve il is held constantly and quietlyat the necessary fixed distance from seat ib to maintain the desiredpressure.. In some prior devices there was a tendency for this Valve topound or vibrate. Itis pointed out that even if some liquid should leakpast valve ii it will pass into .reliefpassage lila. As the leakagecontinues the pressure will build up in passage i 0a and when it gets toa point much above the pressure in chamber l0e1 and I 0e2 'it will movevalve l2 and merely pass out into the lowv pressure line. It will benoted that the device is symmetrical and that valve portion 34a isnormally centrally disposed over the port of passage i0. Portions 36hand 34o are symmetrical with relation to the ports adjacent the same.The device can thus be used to control the pressure Whether pipe 38 isthe discharge or relief line or whether pipe 36 is the discharge orrelief line. The device is thus a duplex device. 'Ihe springs 23 and 22can be set so as to be compressed at different pressures. For instance.spring 23 could be set so that the device will operate to permit passageof liquid to low pressure line 38 at 1000 pounds and spring 22 could beset so as to yield upon a pressure of 400 pounds so that liquid would berelieved into line 3S if line 38 were made the high pressure line.

Attention is alsocalled to the fact that there are no small passagesthrough which the liquid must pass in the operation of the device. The

This interval. in which any leakage ports opening into control passagei0f are all of large size and there is no, chance for dirt or foreignmatter to accumulate and clog these passages, which action has occurredin devices having small passages or needle valve structures. It willalso be seen that the device can be readily vented to remove all chanceof-any air accumulation or any adverse action by the accumulation ofair. Since the device is, as stated, symmetrical and the parts at oneside are identical with the parts at the other, it is believed that itwill not be necessary to describe the operation should the relief lineor the discharge or exhaust line be in conduit 36.

One important feature of the device is that the full pressure from thehigh pressure line 36 is applied to the valve 34. In devices of theprior art the liquid has had to pass through a small opening and thisthrottles down the pressure. In such a case the -full pressure of thehigh pressure line is not applied to the valve causing` operation of thedevice. The present construction acts with'greater precision andthedevice operates when the desired pressure is reached. The device willalso operate to hold the pressure very close to the desiredorpredetermined pressure.-

It is also pointed out 'that when valve portion 34o closes theportofpassage |011 the pressure from the high pressure line is cut of! frompassage ltd.l The same action would occur, of course, if the valve wereoperating the otherway when portion 3Ib would close the port of passagelok1 and cut on the pressure from chamber we. Such laction insures apositive opening of the valves Hand l2 respectively.

From the above description it will be seen that I have provided a verysimple and eiiicient control device for liquids under pressure and one lwhich will function accurately and eiiiciently to relieve the liquid ata certain pressure. All parts are controlled by the pressure oi' theliquid and the device acts with great precision. As stated there is' noappreciable period of leakage before the device operates and there areno small passages to become clogged with dirt or other foreign materialand interfere with the operation. The device is exceedingly simple andcompact and can be easily and inexpensively produced. The devicerequires little or no attention` for maintenance. The same has beenamply demonstrated in actual practice .and found to be very successfuland emcient.

It will, of course, be understood that various changes may vbe made inthe form, details, arrangement and proportions of the parts, withoutdeparting from the scope of applicants invention, which generallystated, consists in a device capable of carrying out the objects aboveset forth, in the parts and combinations of parts disclosed and definedin the appended claims.

What is claimed is:

` l. A device for controlling the flow of liquid from one linecontaining liquid under pressure to another line containing liquid underlower pressure comprising a chamber having openings at opposite ends,valves closing said openings;

plungers for operating said valves, a control passage, a relief portcommunicating with said control passage and leading to said chamber,pairs of ports leading respectively from said control passage atopposite sides oi said iirst mentioned port, the ports-- of each pairhaving passages leading to opposite sides of said plungersYrespectively, a control valve in said control passage having a portionnormally closing said iirst mentioned port and having portions spacedfrom said first mentioned portion forming chambers in said controlpassage with which said pairs of ports respectively communicate, portsat the other ends of said last mentioned portions respectively havingpassages connected to said first and second mentioned lines and yieldingmeans at each end of said control valve holding the same in setposition, said iirst mentioned portion of said control valve beingnormally disposed centrally over said first mentioned port and saidother valve portions and ports being disposed symmetrically with respectto said first mentioned port.

2. The structure set forth inl claim 1 and means for varying thepressure at which said means will yield whereby said means may be dif-4i'erentially adjusted to control the pressure in either line used as thehigh pressure line.

3. A valve for relieving hydraulic pressure from one line containingliquid under pressure to another line containing liquid under lowerpressure comprising a member having a relief passage therein, a valveclosing said passage, a plunger associated with said valve, a chamberadjacent said passage at'one side of said plunger to which said rstmentioned line is connected, a second chamber at the opposite'side or"said plunger, a pilot valve having spaced portions thereon, a passageleading from said reliefvpassage normally closed by one of saidportions, spaced ports at either side of the other portion connected toa passage leading to said first mentioned chamber, a passage leading tosaid second chamber having a port disposed between said portions andthus communicating with said last mentioned passage and an adjustableyielding means holding said pilot valve in set position whereby pressurewill pass from said rst mentioned line to both sides of said plunger andwill l' operate on one of said portions of said pilot valve to closesaid passage leading to said second chamber andopen said port leadingAfrom said relief passage whereby said plunger will be operated to opensaid first mentioned valve.

Y 4. A device for controlling the iiow of liquid from one line.containing liquid under pressure to another line containing liquid underlower` pressure comprising a member having a relief passage therein,valves at opposite ends of said passage normally closing said passage,plungers associated with said valves respectively adapted to be actedupon by pressure at opposite sides thereof tending to open or close saidValves, means connecting said rst mentioned line to both sides of one ofsaid plungers,means for connecting said other line to both sides of saidother plunger, a control passage, a passage leading from said controlpassage to said relief passage and a control valve in said controlpassage 7. The structure set forth in claim 6 and pas-y sages disposedat the remote ends of said last mentioned portions of said control valvethrough 4pressure comprising a member having a relief passage therein,valves closing the ends of said relief passage, a pair of chambersadjacent each of said valves respectively adapted to receive liquidunder pressure for opening or closing said valves, a control chamber, apassage leading from said control chamber to said relief passage,passages leading from said control chamber and disposed equal distancesat either sideof said last mentioned passage and leading to one of eachof said pairs of chambers respectively, passages spaced equally fromsaid last mentioned passages respectively and leading from said controlchamber to the other chamber of each of said pairs respectively, acontrol Valve tting in and movable in said control chamber having acentral portion normally disposed centrally over said second mentionedpassage and having portions spaced having a land normally disposedcentrally over and closing said last mentioned passage and having landsspaced from said land for controlling said two mentioned meansrespectively.

5'. The structure set forth in claim 4, yielding means at each end ofsaid control valve and means for varying the pressure at which saidmeans will yield.

6. A device for relieving hydraulic pressure.

from one line containing liquid under pressure to another linecontaining liquid under lower pressure comprising a member having arelief passage therein, valves closing the ends of said relief passage,a pair of chambers adjacent each of said valves adapted to receiveliquid under pressure for opening or closing said valves, a controlchamber, a passage leading iromsaid control chamber to said reliefpassage, passages leading from said control chamber at each side ofsaici last mentioned passage to one of the chambers of each of saidpairs respectively, passages leading from said control chamber spacedfrom said last mentioned passages respectively and leading to the otherchambers of said pairs respectively and a control valve in said controlchamber having a central portion controlling said second mentionedpassage and having portions spaced therefrom for controlling said twolast mentioned two v sets of passages, said control valve being conequaldistances therefrom for controlling said last two mentioned sets ofpassages and means for applying the pressures of said lines respectivelyto said control valve at the remote endsof said last mentioned portionsthereof and yielding means engaging the ends of said control valve, saidpassages from said control chamber being arranged symmetrically withrespect to the center of said passage leading from said control passageto said'relief passage. i Y

l0. A device for relieving hydraulic pressure from one line containingliquid under pressure to another line containing liquid under lowerpressure comprising a member having a relief passage therein, valvesclosing' opposite ends of said passage, a pair of chambers adjacent eachof said valves adapted to receive liquid under pressure for opening orclosing said valves, plungers in said chambers connected to said valves,a controly chamber, a passage leading from said control chamber to saidrelief passage, passages leading and a control valve in said controlchamber havstructed and arranged to be operated upon the v liquid insaid first mentioned line.

ing a central portion controlling said second mentioned passage andhaving portions spaced therefrom for controlling said two last mentionedsets of passages, said two last mentioned sets of pas sagesA beingsymmetrically disposed at either side of and with respect to said secondmentioned passage and said portions of said control valve being'disposed symmetrically with respect to said centro] portion, saidcontrol valve being construct-,ed and arranged to be operated upon theattainment of a'predetermined pressure of said liquid in said firstmentioned line. l

11.A device for controlling the flow of liquid from one line containingliquid under pressure to another line containing liquid under lowerpressure comprising a member having a relief passage therein, a valveadapted to Y close said passage, a bore-in said member, a plungerconnected to said valve movable in said bore and forming chamberstherein at .Opposite sides of said plunger, a passage leading from thecham- Abers at the side of said plunger adjacent said valve to said.iirst mentioned line, a control passage in said member, a controlmember movable therein having spaced lands, yielding means re sf'stingmovement of said control member in one direction, a passage leading fromsaid last men tioned chamber and having branches with ports at eitherside of one of said lands in the normal position of said control member,a passage leading from said other chamber and having a. port dis` posedbetween said lands in the normal position er pressure comprising amember having a relief of said control member and a passage leading topressure comprising a member having a relief passage therein, a pair ofvalves controlling the admission .of liquid to said passage, plungersassociated with said valves respectively having chambers at either sidethereof and adapted to be moved by pressure of said liquid, passagesconnesting saidl lines respectively with one of the chambers of eachofsaid plungers, a control passage spaced from said chambers. a passageleading from said relief passage and having a port communicating withsaid control passage, a control member in said control passage having acentral land disposed centrally over said port in the normal position ofsaid control member, yielding means resisting movement of said controlmember in oppositer directions and passages leading from each of saidchambers at opposite sides of said plungers respectively and havingspaced ports communicating with said control passages at each side ofsaid rst mentioned port, said control member having lands spaced fromsaid first mentioned land for con'- trolling said last mentioned ports,said -last mentioned ports being disposed symmetrically with relation tosaid first mentioned port and at opposite sides thereof.

13. A device for controlling the flow of liquid from one line containingliquid under pressure to another line containing liquid under lowpassagearrangedto be connected with said secv ond mentioned line, a valveclosing said relief passage, chambers adjacent said valve adapted tohave liquid under pressure thereinfor clos-v ing or opening said valve,a control-passage, means for connecting said first mentioned line toboth of said chambers including a passage from one of said chambers tosaid control passage, -a passage leadingl from said controlpassage tosaid relief passage, a control valve in said control passage movableupon a predetermined,

pressure of said liquid'for opening saidv last mentioned passage andclosing said second mentioned passage to cause a differential pressurein said chambers for opening said valve, and a third valve closing saidrelief passage acted on by liquid from said second mentioned line andadapted to be opened when said iirst mentioned valve is opened.

14. A device for controlling the flow of liquid from one line containingliquid under pressure to another line containing liquid under lowerpressure comprising a member having a relief passage therein adapted tobe connected `to said second mentioned line, a valve closing said reliefpassage, a plunger associated with said valve adapted to be operated onby pressure at opposite sides to close or.open said valve, a controlpassage, ports having passages within said mem--` ber leading from saidcontrol passage to said relief passage and to opposite sides of saidplunger respectively and a control valve in said control passage movableby liquid under pressure in -said rst mentioned line at a certain pointand comprising spaced lands tting said control passage to open said portleading to said relief passage and to close a port through whichpressure from said iirst mentioned line is applied to one side of saidplunger to cause movement of said plunger to open said rst mentionedvalve, said pressure being applied to one of said lands for moving saidcontrol valve, two of said lands of said control valve being arrangedfor closing and opening said ports respectively and so spaced that saidport leading to said relief passage is opened just as said port leadingto said one side of said plunger is closing whereby there is noappreciable period of leakage into said first mentioned port before saidfirst mentioned valve opens to relieve the pressure.

GAROLD A. KANE.

